KR20090026163A - Base station, user device and method for utilizing a plurality of resource block sizes - Google Patents

Abstract

A base station is provided with a scheduler for deciding at least a resource block to allocate to a data channel; a means for generating a transmission signal for transmitting the data channel corresponding to scheduling information from the scheduler; a means for transmitting the transmission signal to a user device; and a means for adjusting the size of the resource block.

Description

BASE STATION, USER DEVICE AND METHOD FOR UTILIZING A PLURALITY OF RESOURCE BLOCK SIZES}

TECHNICAL FIELD The present invention relates to the technical field of mobile communications, and more particularly, to a base station, a user apparatus, and a method for using a plurality of resource block sizes.

In this kind of technical field, research and development on the next generation communication method is progressing rapidly. In the next-generation communication system, in order to improve the utilization efficiency of radio resources from the present, resource allocation to a user apparatus includes time scheduling and frequency scheduling. Both are used.

1 shows a state in which radio resources are allocated to three or more users. As shown, the radio resource is allocated as a unit a block of size that is occupied at any bandwidth F _RB , for example 375 kHz, and at any time period T _RB , for example 0.5 ms. This unit block is called a "resource block" (RB) or "chunk". Regarding the frequency axis direction and the time axis direction, by first allocating one or more resource blocks to users in a better channel state, data transmission efficiency (throughput) of the entire system can be improved. Which resource block is assigned to which user is determined at the base station, and the process is called scheduling. In the scheduling, some fairness may be considered in addition to the channel status. Scheduling, resource blocks, and the like that are assumed in the present application are known.

Disclosure of the Invention

Challenges the invention seeks to solve

The inventors of the present invention, in the basic research of the present invention, relates to the relationship between resource block size, scheduling effect, signaling overhead, and resource utilization efficiency. Planted.

2 is a diagram showing the interrelationship thereof. As shown in the first row of the diagram, when the resource block size is small, the resource blocks can be allocated precisely in accordance with the channel status, and the improvement effect of throughput as a whole system can be expected. On the contrary, if the resource block size is large, it is difficult to allocate the resource blocks precisely, and the degree of improvement in throughput as a whole system is small. In general, channel fluctuations vary greatly in the frequency direction than in the time direction, but the same tendency occurs in either direction with respect to the size of the resource block and throughput.

As shown in the second row of the diagram, when the resource block size is small, since there are a large number of resource blocks, the amount of information of scheduling information indicating which resource block is used for which user increases. That is, there is a concern that the signaling overhead increases. On the other hand, when the resource block size is large, the number of resource blocks is small, so the signaling overhead is small.

As shown in the third row of the diagram, when data transmission of a small data size such as voice packet (VoIP) or simple delivery confirmation information (ACK, NACK) is performed, if the resource block size is large, resource waste may occur. There is concern. This is because one resource block is used by one user. In this regard, if the resource block size is small enough, such waste is also reduced.

As described above, it is difficult to determine a preferable resource block size in view of all the improvement of throughput of the entire system, reduction of signaling overhead, and resource utilization efficiency. However, the resource block size is one type in the next-generation communication system. Therefore, there is a concern that depending on the communication situation, any of the above aspects must be sacrificed.

An object of the present invention is to improve the transmission efficiency of data of various sizes and to effectively utilize resources while reducing signaling overhead.

Means to solve the problem

The base station used in the present invention includes a scheduler for determining at least a resource block allocated to a data channel, means for creating a transmission signal for transmitting the data channel in accordance with scheduling information from the scheduler, and the transmission signal. Means for transmitting to the user apparatus and means for adjusting the size of the resource block.

Effects of the Invention

According to the present invention, it is possible to improve the transmission efficiency of data of various sizes and to effectively use resources while reducing the signaling overhead.

1 is a diagram schematically showing a state in which resources are allocated to three or more users.

2 is a diagram showing a correlation between resource block size, scheduling effects, signaling overhead, and resource utilization efficiency.

3 is a block diagram of a transmitter of a base station according to an embodiment of the present invention.

4 is a block diagram of a receiving unit of a user apparatus according to an embodiment of the present invention.

5 is a diagram illustrating a state in which resource blocks having different sizes are used.

6 is a diagram schematically showing a channel state that fluctuates gently and violently.

7 is a diagram illustrating an example of an arrangement pattern of resource blocks.

8 is a diagram illustrating a state in which resource blocks are designated by a bit mapping method.

9 is a diagram illustrating a state in which resource blocks are designated by a table lookup method.

Explanation of the sign

31 Sending buffer

32 OFDM transmitter

33 scheduler

34 Pattern Determination Unit

35 memory

41 OFDM receiver

42 Resource East Government

43 placement pattern determination unit

44 memory

45 CQI Measuring Unit

Invention  Conduct  for Best  shape

3 is a block diagram of a transmitter of a base station according to an embodiment of the present invention. 3 shows a transmission buffer 31, an OFDM transmitter 32, a scheduler 33, a pattern determiner 34 and a memory 35. As shown in FIG.

The transmission buffer 31 accumulates downlink transmission data and outputs the data according to the scheduling information.

The OFDM transmitter 32 creates a transmission signal for wireless transmission of downlink data according to scheduling information. More specifically, the transmission data is encoded at the indicated channel code rate, modulated by the indicated data modulation scheme such as 16QAM, and OFDM modulation is performed by fast inverse Fourier transform. Is transmitted from the antenna with the given guard interval.

The scheduler 33 executes time scheduling and frequency scheduling based on the downlink channel quality indicator (CQI) reported from the user device and the notified resource block size, and outputs scheduling information. The scheduler 33 determines scheduling information so that a resource block is allocated to a user having a better channel state based on the downlink CQI. The scheduling information includes information indicating a combination of modulation schemes and channel coding rates (MCS numbers), in addition to information indicating which resource block is assigned to which user. In order to determine the scheduling information, not only the CQI but also the amount of untransmitted data accumulated in the transmission buffer and an index for achieving fairness may be considered.

The pattern determination unit 34 adjusts the size of the resource block based on both or one of the data size of the transmission data and the CQI. In this embodiment, resource blocks of two sizes are provided, which are used depending on the data size and the CQI.

The memory 35 stores an arrangement pattern of resource blocks. An allocation pattern of resource blocks and usage examples thereof will be described later.

4 is a block diagram of a receiver of a user apparatus according to an exemplary embodiment of the present invention. In FIG. 4, the OFDM receiver 41, the resource identification part 42, the placement pattern determination part 43, the memory 44, and the CQI measurement part 45 are shown.

The OFDM receiver 41 derives a control data channel and a traffic data channel from the received signal. More specifically, the OFDM receiver 41 removes the guard interval from the received signal, performs the OFDM demodulation by fast Fourier transforming the received signal, and demodulates the data according to the scheduling information notified from the base station. Perform data decoding and derive a control data channel and / or a traffic data channel.

The resource identification part 42 outputs mapping information which specifies the position of the resource block on the time axis and the frequency axis based on the scheduling information and the arrangement pattern of the resource block.

The arrangement pattern determination unit 43 extracts the arrangement pattern corresponding to the pattern number notified from the base station from the memory 44, and notifies the resource identification unit 42 of the content.

The memory 44 stores the arrangement pattern of the resource block together with the pattern number.

The CQI measuring unit 45 measures the CQI of the received signal. The measured downlink CQI is reported to the base station at a predetermined frequency.

The operation will be described with reference to FIGS. 3 and 4. The transmission data is stored in the transmission buffer 31, input to the OFDM transmission unit according to the scheduling information, and processed into channel transmission, data modulation, mapping to resource blocks, fast inverse Fourier transform, and the like as a transmission signal for wireless transmission. Is converted and sent. The scheduling information designates a channel encoding scheme, a data modulation scheme, a resource block, and the like. In this case, resource blocks of different sizes are used as necessary in this embodiment.

5 shows a state in which two types of resource blocks having different bandwidths are used. In the example of illustration, two small resource blocks F _RB1 XT _RB and two large resource blocks F _RB2 XT _RB are alternately arranged in the frequency axis direction. The pattern determination unit 34 may determine the allocation pattern of the resource block based on the CQI (not limited to the CQI, but any amount indicating the channel state of the downlink) reported from the user apparatus. For example, it is assumed that the channel state includes a gentle range B ₁ and a severely varying range B ₂ , as shown in FIG. 6. In this case, it is preferable to allocate a resource block of a relatively large size in the range B ₁ , and it is preferable to allocate a resource block of a relatively small size in the range B ₂ . This fits not only in the frequency axis direction but also in the time axis direction. In this embodiment, the pattern determination unit 34 selects an appropriate arrangement pattern from the memory 35 from a predetermined number of arrangement patterns provided in advance based on the downlink CQI. Such an arrangement pattern may be distinguished by any number (pattern number).

Alternatively, the pattern determination unit 34 may select an arrangement pattern depending on the type of transmission data. For example, it is preferable to provide a resource block of a large size for data transmission of a relatively large data size, and to provide a resource block of a small size for data transmission of a small data size such as voice data (VoIP). The arrangement pattern may be selected in accordance with the situation of such transmission data. More preferably, it is preferable that a more appropriate arrangement pattern is determined based on both the CQI and the transmission data.

The user apparatus restores the received signal based on the arrangement pattern used in the base station. Which resource block arrangement pattern is used is determined by the pattern determination unit 34 of the base station in FIG. 3, and the decision content is notified to the scheduler 33. The information (specifically, the pattern number) and the scheduling information are notified to the user apparatus on an appropriate control channel. The user apparatus extracts the pattern number and scheduling information by restoring the received control channel. The pattern number is given to the arrangement pattern determination unit 43 in FIG. The arrangement pattern determination unit 43 notifies the resource identification part 42 of the information on the arrangement pattern designated by the number based on the notified pattern number. The resource identification part 42 specifies the resource block containing the data forwarded to the own station according to the specified arrangement pattern and scheduling information, and notifies the OFDM receiver 41. The OFDM receiver 41 extracts and restores the data channel to the local station according to this information.

In the example shown in FIG. 5, the arrangement of small resource blocks and large resource blocks is shown to be invariant in time, but the present invention is not limited to such an example. For example, such an arrangement pattern may be changed in any long period T. For example, when T _RB is about 0.5 ms, the update period T of the batch pattern may be about 100 ms.

7 shows an example of an arrangement pattern of resource blocks. In the example of illustration, although a resource block is designated by consecutive numbers in the frequency axis direction irrespective of the magnitude | size of the magnitude | size, the information and number which distinguish a magnitude | size and a case may be combined. It is not essential that the position and number of resource blocks in the time axis and frequency axis directions are fixed in one update period. One or more of any appropriate arrangement pattern such as shown in the figure and other than that may be included in the update period T. In either case, the arrangement pattern to be used may be fixed during the update period. In view of adaptively following the resource block size and position to various channel states and communication states, it may be desirable to select an appropriate one each time without having to fix the placement pattern in one cycle. However, in this case, the amount of information of the signaling channel (control channel) for notifying what the arrangement pattern is is increased. In view of lowering the increase in the amount of information of the control channel, it is preferable to fix the pattern within one update period while limiting the number of patterns used. In this way, for example, an arrangement pattern can be specified only by a pattern number. In other words, the ideal control channel to which the present embodiment is applied may be increased by only 2 bits (4 patterns). The notification of the arrangement pattern to the user apparatus may be performed for each update cycle, but the cycle may be relatively long as described above. Therefore, the update notification of the batch pattern may be transmitted as an L1 / L2 signaling message or may be transmitted as an L3 message.

8 shows a state in which resource blocks are designated by bitmapping. As shown in the figure, for each user device, information indicating an allocation status is provided for each resource block. That is, with respect to the user device 1, information indicating whether or not the first resource block is allocated (1 or 0), whether or not the first resource block is allocated (1 or 0) is provided. do. As an example, "1" represents an assigned state, and "0" represents an unassigned state. Similarly, allocation information is provided for each resource block for the user apparatuses 2, 3, ....

9 shows a state in which resource blocks are designated by a table lookup method. In this example, numbers for distinguishing the user apparatuses A, B, and C are provided first. In the example of illustration, user apparatuses A, B, and C are associated with 1, 2, and 3, respectively. Then, to which user apparatus each of the resource blocks is allocated is specified. Which resource block is assigned to the first resource block, which resource block is assigned to the second resource block, and so on. The table lookup method may be advantageous in terms of efficiently specifying only the information that is allocated.

In the above embodiment, only two resource blocks are provided in size. However, more than two resource blocks may be provided as necessary. In addition to resource blocks having different bandwidths, resource blocks having different transmission times T _RB may be provided. However, in view of preferentially coping with fading fluctuations in the frequency axis direction, it is desirable to focus on providing resource blocks having different bandwidths. In the above embodiment, the size of the large resource block is set to twice the size of the small resource block. More generally, one size may be adjusted to an integer multiple of the other size. For example, if the bandwidth of a large resource block is an integer multiple of the bandwidth of a large size, when the various arrangement patterns in which resource blocks of different sizes are mixed are used in combination, it is possible to always occupy the same band throughout the system. This is preferable from the viewpoint of using the band without waste.

While the present invention has been described with reference to specific embodiments, each embodiment is merely an example, and those skilled in the art will understand various modifications, modifications, alternatives, and substitutions. Descriptions have been made using specific numerical examples to aid the understanding of the invention. Unless otherwise specified, their numerical values are merely examples and any appropriate values may be used. The division of each embodiment is not essential to the present invention, and two or more embodiments may be used as necessary. For convenience of explanation, the apparatus according to the embodiment of the present invention has been described using a functional block diagram, but such apparatus may be realized in hardware, in software, or in a combination thereof. The present invention is not limited to the above embodiments, and various modifications, modifications, alternatives, substitutions, and the like are included in the present invention without departing from the spirit of the present invention.

This international application claims priority based on Japanese Patent Application No. 2006-169428 filed on June 19, 2006. The full text of this application is incorporated in this international application.

Claims (10)

A scheduler for determining at least a resource block to allocate to a data channel; Means for producing a transmission signal for transmitting the data channel in accordance with scheduling information from the scheduler; Means for transmitting the transmission signal to a user apparatus; And Means for adjusting the size of the resource block. The method of claim 1, A base station, characterized in that an arrangement pattern for designating a position in at least one of a time axis and a frequency axis of resource blocks having different sizes is repeatedly used in the scheduler at any period. The method of claim 1, Wherein the choice of placement pattern is limited to a predetermined number less than the total number of possible deployments of the resource block. The method of claim 1, The base station, characterized in that the choice of the size of the resource block is limited to a predetermined number. The method of claim 3, wherein A base station, wherein the size of one option is equal to an integer multiple of the size of another option. The method of claim 1, And a control channel for notifying the user equipment of the scheduling information includes information indicating an allocation status for each resource block for each user equipment. The method of claim 1, And a control channel for notifying the scheduling information to a user device includes information indicating to which user device each resource block is allocated. In the method used in the base station, Determining at least at a scheduler a resource block that allocates a data channel; Creating a transmission signal for transmitting the data channel according to scheduling information from the scheduler; And Transmitting the transmission signal to a user device; And the size of the resource block is adjusted according to both or one of a downlink channel state and a data size. Means for receiving a signal from a base station, the signal including scheduling information specifying at least a resource block assigned to a data channel; Means for extracting, in accordance with the scheduling information, a channel in front of the own station from the received signal; And And arrangement pattern discrimination means for discriminating, based on a control channel received from a base station, an arrangement pattern for designating a position in at least one of a time axis and a frequency axis of resource blocks having different sizes. And the channel in front of the own station is extracted in accordance with the determined arrangement pattern. In the method used in the user device, Receiving a signal from a base station, the signal including scheduling information specifying at least a resource block assigned to a data channel; And And extracting, from the received signal, a channel to the local station according to the scheduling information. An arrangement pattern specifying a position in at least one of a time axis and a frequency axis of resource blocks having different sizes is determined based on the control channel received from the base station, and the channel before the station is extracted according to the determined arrangement pattern. Characterized in that the method.

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